Thermovision monitoring of rotary kilns
20. 6. 2020
Presentation: coronavirus screening of febrile conditions
25. 6. 2020The integration of thermal camera fever screening into public health and safety protocols has become increasingly critical in monitoring and preventing the spread of infectious diseases. To achieve precise and reliable temperature measurements, it is essential to adhere to a specific set of procedures, ensuring the efficacy of fever screening initiatives.
Optimal Screening Environment
Temperature screenings yield the most accurate results when conducted indoors, where environmental variables can be controlled. In situations where indoor screening is not feasible, selecting an area that closely replicates indoor conditions becomes necessary. This control over the environment helps in mitigating factors that could skew temperature readings. For screenings to reflect true temperatures, the area must maintain an air temperature range between 18°C and 24°C and a relative humidity between 10% and 75%. Factors such as wind and air conditioning,
which can cool the face and affect temperature readings, should be minimized. Additionally, it's imperative to conduct screenings away from direct sunlight, as it can warm the skin and lead to inaccurate measurements.
Preparation of Individuals
The accuracy of thermal screenings is also dependent on the preparation of the individuals being screened. It is crucial for the person to directly face the thermal camera lens without any obstructions, such as glasses, which are opaque to LWIR thermal cameras and can interfere with accurate temperature detection.
Camera Configuration and Calibration
Setting up the thermal camera with precise measurement parameters is vital for accurate temperature readings. Operators must carefully select settings such as emissivity and reflected apparent temperature. These settings are critical in adjusting the camera to accurately measure the surface temperature of the skin. The spatial resolution of the camera plays a significant role in the accuracy of the measurements. A resolution of at least 1 mm per pixel on the face of the person being screened is required. This specification influences the distance between the camera and the individual, ensuring that the thermal image is clear and detailed for accurate analysis.
For optimal results, using a thermal camera with a higher resolution of 640×480 pixels is recommended. This higher resolution allows for adherence to technical standards such as the IEC 80601-2-59, facilitating screenings from a distance of at least 1 meter, depending on the camera's angle of view.
Continuous calibration of the thermal camera using a black body is essential for maintaining accuracy. This calibration ensures the camera's measurements remain reliable over time, adjusting for any potential drifts in sensor accuracy. The black body used for calibration should be stable in temperature and prominently visible in the camera's thermal image to ensure consistent recalibration.
Target Area for Measurement
The most accurate area for fever screening measurements is medially adjacent to the inner corner of the eye. This site is preferred due to its proximity to the carotid artery, reflecting the body's core temperature more accurately than other facial areas. Focusing on this specific area ensures that the readings are representative of the individual's true body temperature, rather than surface skin temperature variations.
In conclusion, thermal camera fever screening is a sophisticated process that requires careful attention to environmental conditions, individual preparation, camera setup, and specific measurement techniques. By meticulously following these guidelines, organizations can significantly enhance the accuracy and reliability of their fever screening processes, contributing to the health and safety of communities.